In this work we propose and demonstrate that time-resolved optical spectroscopy in the spectral region 700-1040 nm, on
a picosecond time scale, is a valuable technique for non-invasive wood characterization. Two different wood types have
been considered, fir and oak chestnut as an example of softwood and hardwood, respectively. Wood samples have been
measured in three different conditions: dry, wet and degraded by an ozone treatment. The two types of wood show
different absorption and scattering spectra according to the treatment, revealing both chemical and structural changes.